I think we should either develop a plan that makes LW fully functional at the three roles mentioned above (and any others that are raised), or we should close down posting and commenting on LW (while maintaining it as an archive).

First, I wonder who this "we" is. Does the "we" discussing this include any people with the power to do any of it?

I don't agree with shutting it down. Post warning message banners if you like, but I believe in the free market. I'm not talking about money or the invisible hand; I'm talking about the idea that you shouldn't try to decide what's good for other people. If people want to keep using LW, their use of it is their vote that it's useful. If people stop believing it's useful, they'll stop using it. If they still believe it's useful to them, who are you to overrule them?